Continuous flow reciprocating pump



Dec. 16, 1941.

Filed Jan. 4, 1941 2 Sheets-Shee'rl 41 2 sheets-sheet .2

Filed Jan. A4, 1941 Patented Dec. 16, 1941 UNITED?- John-lames Milton Lee?Y San Diego, Calif. v Application January 4, 1941, Serial No. 373,115 whims.. i. (c1. 74-44) My invention is designated as pertaining] toa pump as this presents oneuse for a certain feature of my invention. J In pumps operated bya reciprocating action such as through the medium of a crank operating a connecting rod orpitman andthis having a connection to the pump plunger or piston, the crank in the'usual -procedurefollows a circular motion. This of course-causes the piston or plunger to come tol rest at opposite ends of the stroke before it changes yits vdirection of movement. The center line through'the'cr'ank at these positions is sometimes designated a dead center. As the crank approaches this deadcenter line there is a gradual deceleration of the pitm'an and'hence of the pump vpiston or plunger. Moreover the pumping action, that is, the movement of the fluid by the plunger or piston is ata standstill as the crank passes through the dead-center line: 'I'his in certain types of pumps is .a disadvantage and moreover the stroke of the pump, that vis;.of the piston or plunger; is limited to thediameter of the circle which` is the throw of the crank.r f

One of the objects and features of my invention is to produce in the pitman or connectingA rod an increased length of stroke and hence develop-the piston or plunger with av similarincreased length of stroke over that of the diameter: of the crank circle. Preferably the increased length of the stroke is developed when the crank i'sfatthe outer .part of the crank circle in itsrela'tionship to the pump rod and the plunger or piston. A further feature of my invention in this regard is to shift the rod in a longitudinal motion when the crank is rapidly decelerating the reciprocating motion to substantially maintain a constant rod and piston speed while the crank passes through the dead center. A further feature of this invention is that the rod and hence the piston or plunger comes to a stop in changing' its direction of motion after the crank has passed the dead center line.

Considered in more detail, my invention utilizes a guide track of a suitable cam shape on which a roller rigidly connected tothe pitman or connecting rod may ride as the crank moves the pitman or connecting rod through the line of dead center in'relationto the circular motion of the crank connected end of the rod. This guide cam or track is so shaped togetherxwith the crank pin being fitted in a slot in the rod head so that an additional lift is given to the rod and a higher rate speed of travel than the longitudinal component of the motion of the crank as it passes this dead center line. When this invention' is appliedrto a pump it develops. an improved' pumping actionof the plunger or piston connected either to a single or a double pump.

rMy invention also comprehends'a double acting pump of the reciprocating plunger or piston type in'which the two plungers or pistons operate substantially simultaneouslyv in opposite directions. When applied to a vertical pump the lower plunger giving the initial suction and lift on its upstroke and at the same time the upper plunger is moving downwardly' transferring the fluid through'the valve inthe second plunger, then on the opposite directionof motion the plungers separate, the upper plunger' givingl a direct lift to the fluid while the lowerplunger forces the fluid through its valve. In this downward stroke of the lower or intake plunger as the upper plunger is creating a suction the flow of liquid through the standing valve of the lower plunger is increased over that due to the displacement of the single lower plunger. Likewise whenthe plungers approach 'and` the space therebetween is decreased, the amount of liquid forced through the Valve of the vupper plunger is greater than that due to the displacement of 'such upper plunger in its single downward stroke. Y y Y Another feature of my invention is operating both of the plungers by cranks each of which may have the same throw or `circle of rotation, the pitman of one crankbeing connected to the plunger' rod of the lower plunger and the other pitman being connected to a plunger sleeve of the upper plunger, such sleeve operating over the plunger rod. By this construction although each plunger has a stroke equal to the diameter of the circle ofthe crank throw,V nevertheless the two plungers working in opposite directions give an effective stroke of4 double the circle of the crank throw.

d A further characteristic of my invention is the employment of the pitman rod .lift for both of the pitmans, one of which operates the lower plunger and the other the upper plunger so that thesel plungers lhave a positive liftl motion as their respective cranks pass through the upper dead center, this being accomplished by the crank pins operating in slots and utilizing the guide and lift cams.

AMy invention is illustrated in-connection with the accompanying drawings, in Which:

Fig. 1 may be considered as an elevation taken iny the direction of the arrow I of Fig. 3 showing the crank vconnection of the pitmans, the lift cams and the connections to the plunger rod and plunger sleeves respectively with the cranks diahead works or drive equipment II has two bearings I 2 and I3 mounted on a suitable support not illustrated, this forming a journal for the crank shaft I4. Such shaft is illustrated. asbeing driven by a pulley I5. For convenience a somewhat heavy disk I6 is usedto form thetwo cranks, one of which has a crank arm I'I andthe other a crank arm I8, each of these arms being connected by the crank pins I9 and.20.` The pitmans and pitman heads are substantially similar, therebeing a first pitman 25 connected by a wrist pin assembly 2B to a. plunger rod. 21. This rod is used to operate the lower plunger hereunder described` The second pitman 35 is connected'by its head to the other crank pin 2) .and through the medium of a wrist pin assembly 3Ivattaches to across head32. This cross head operates rin guide rails 33 through the medium of travelling slides 34 "and the cross head is connectedto a plunger sleeve'35 which reciprocates the upper plunger as hereunder described. Each of the pitman heads designated 4D, note Fig. 4, is of the same or similar construction having a slot 4I formed therein, the head being illustrated as having two parts boltedl together. The head is also provided with a lift rod extension 42 having astub axle 43-mountedA thereon andaroller 44. There are two similar cam guide tracks50 each illustrated as 'having a bracket 5I secured to one of the bearings I2 or I3or to some other suitable support and each having a-projecting cam track 52. This cam track may vary in shape and may for instance be that shown in the dotted line 53 in Fig. 4. It is to be noted that it is necessary to have aspace between the side edges of each cam track and the disk or fly wheel I6 to allow passage Vof the extension rod 42 of the pitman heads as these lift above the crank pin in the rotation of the crank shaft and the. cranks. The rollers are therefore oifset to one side and engage the4 cam surfacev at the timed interval for which the cam track is designed as hereunder set forth.

Referring to Fig. Y4, on the lift of the pitman rod by the respective crank pins, the crank pin engages the upper end of the slot 4I of the pitman head, this position being indicated bythe numeral .65. At the desired position when the crank approaches the upper end of its stroke the roller 44 engages the cam track 52 at the position indicated atSI thereon to and past the dead centerwhich is indicated by the dotted line B2. The cam track 52 develops a lift on" the roller 44 and hence through the medium of the stub shaft 43 the rod extensiony 42 develops a lift on the pitman bringing the crank pin into a position intermediate the two ends of the slot for instance as indicated by the numeral- 63. The direction of rotation is indicated by the arrow 64 and it will be noted that when the extension arm 42 is offset in fa. trailing direction as to the rotation that the crankl pin is in its uppermost dead center position before' thev roller' 44 is in line with this dead center. The curve of the cam 52 still gives a.

slight elevating action as the crank pin passes by the dead center. The track 52 may be designed to elevate the pitman rod until the crank pin has moved to such a position that it approximately engages the lower end of the slot 4I as indicated at 65. It is then necessary to have an abrupt downward curve or termination 66 of the track 52 to allow the roller 44 to clear as from this point onwardly the wrist pin is giving a positive downward thrust on the pitman by engaging the lower end of the slot 4 I On the upward stroke of course it engages the upper end of such slot. In accordance with the particular shape and design ofthe cam 52 fand the length of the slot 4I the amount of extra lift given to the pitman and hence the plunger operated thereby may be determined by the factors desired and may be changed by `changing 'the shape of the cam and the shape of the head, the slot and the arm 42 extending therefrom. In Fig. 4 the line 61 indicates the point of the start` of the lift dueto the cam track and the:roller 44, the line 68 indicates the end of-this auxiliarylift and the space of the two lines '69' indicates the total amount of the additional lift given after the crank has passed the dead center. The total amount of additional lift is the vertical component of the long axis of the slot 4I in the pitman rod head less the diameter of the crank pin.

The :cam tracks are only operative at the upper end ofthe pitman strokes, that is, when the respective crank pins are adjacent the top of their stroke. With 'this type of action there is a certain pause in the lift of the pitmans and hence the respective. plungers at the bottom end of the stroke'for instance in the travel indicated from the crank pin position 65 of Fig. 4 to the crank pin vpositionA 10, the crank pin is exerting a downward thrust on the pitman, the crank engaging the lower end of the slot 4I. Then as the crank pin commences its upward motion on the other side of the circle the pitman is swung to one side untilthe crank pin comes to the positions 'II at the upper end of the slot 4I. The crank pin then exerts a lift on-the pitman and continuing this lift tothe position indicated at 60. In this lower position there is no cam track as above mentioned and hencethe rollers 44 have an idle travel. As above mentioned, the cam tracks are preferably similar for both of the pitmans but it is obvious that if desired these may have a different diameter crank throw and may have diiferent shaped cam lift tracks.

An embodiment of a pump suitable for use with the auxiliary stroke features of a mechanical motion as above described is shown in Fig. 2 in which a .pump barrel is shown with a cap 8l threaded thereto, such. cap having a discharge connection 82. The barrel is not continued downwardly to show the intake for'the liquid as this may be of any conventional type. The head is provided witlra recess 83 havingpacking and a packing gland 34. Operating within the pump barrels there is a. lower plunger assembly 85 and an upper plunger assembly 85. These may be substantiallyA the same in general construction, for instancehaving a plunger disk 81, a valve cage 88 withv .a rim 89 which confines a cupped pump leather 9i)l facing downwardly. Each plunger is shown. as: having a removable Valve seat 9i, the lowerl plunger is indicated as having a ball plug 82 :and thelupperplunger having a cone shaped plug 83, this latter having a perforation 94 therethrough, the valve seats of course having the used.'

proper contact with the particular typeofplug The sleeve 35 which "as ab'ove mentioned is connected to the-cross head- 32 extends downwardly in vthe well,1the pump barrel being supported in any suitable manner. This sleeve has a'sliding viit through the lpacking gland yllr 'and the-packing 83 making ai leak proof ijoint. The sleeve is attached' to the cage of the upper plunger by means ofaierrule Iin'which there is a packing IDI This connects the upper plunger to reciprocate with the cross head. The plunger rod 21 extends downwardly inside of the sleeve 35 passing through an opening in the cross head 32. It has a sliding fit on the packing IUI in the ferrule and operates through a suitable opening in the cage of the upper plunger 86. 'I'he plunger rod is indicated as having a threaded connection to a hub |82 of the cage of the lower plunger 85. The packing lill prevents leakage around the reciprocating plunger rod 21 which rod has a sliding passage through the perforation 94 in the cone plug 93. It is preferable to have a distinct operating clearance between the plunger sleeve 35 and the plunger rod 21 as there need be no sliding contacts between these two elements and the space therebetween may be lled With suitable lubricating oil.

In the illustration of Fig. 2 the two plungers are shown at their closest position. This is when the cranks are in the position shown in Fig. 1, that is, the plunger rod 21 is in its uppermost position and hence the plunger 85 is in its highest position of movement. The pitman 30 operating the cross head 32 and the sleeve 35 is in its lowermost position and hence the plunger 86 is at the bottom of its stroke. As the crank shaft rotates these plungers move apart to the dotted line position as shown in Fig. 2, that is, the plunger 85 moves downwardly and the plunger 86 upwardly. It is presumed that on the upstroke the lower plunger creates a, suction causing the uid from the well to follow the plunger and iill in the space. At the same time as this plunger is moving upwardly it elevates the fluid above the seated ball plug 92. At the same time that the lower plunger has its upstroke the upper plunger has a down stroke forcing the trapped fluid between the two plungers through the cone plug 93. Due to the fact that the lower plunger is moving upwardly while the upper Y plunger is on its down stroke, vmore liquid is forced through the upper plunger than that duev merely to a displacement of such upper plunger but is equal to the displacement of both of the plungers in their stroke. Thenkon the down stroke of the lower plunger against the liquid in the well, it forces fluid through its ball plug to an amount equal to the displacement of such lower plunger on the down stroke plus the suction iiow created by the upper plunger on its upstroke. The total mount of liquid therefore drawn into the space between the plungers in their extreme positions as shown dotted in Fig. 2 is thus an amount double the displacement of the plungers. As the upper plunger is on its upstroke it lifts the amount of fluid thereabove.

'I'he actual lift of course is only the travel of the upper plunger but the effective amount of flow of fluid is that equal to the displacement of both of the plungers. As above mentioned when the cranks have the same throw and the same cam auxiliary lift, the strokes of both plungers are equal but it is not necessary that both cranks have the same circle of rotation, that is, the

same. Vcrank ,thrownor the' same Aauxiliary lift cams.. f

center, there: would be a di'stinctdeceleration vand stoppage of the flow of the fluid but dueto the additional or auxiliary lift given by the cams which carry Vpast Ythe dead centerl line Avof the crank pins, there is a continuity of iluid motion although the velocity changes. 'I'his action when using two plungers operating in opposite direction strokes causes a substantially constant upward movement ofthe fluid being pumped although the velocity change is dependent of course on the position of the crank pins in their respective rotations and power strokes.

Although I have illustrated the slotted arm leading from the head of the pitman as being offset in a trailing direction as to the rotation of the crank pin and at a denite angle in reference to the pitman, it is to be understood that the angle of this slotted arm may be considerably changed and` also that the cam track may vary through a wide range and in fact the track may be a straight line and terminate abruptly without having an easing o curve. Also if desired the slotted arm leading from the head of the pitman may lead the crank pin in a rotation but still the cam track may be positioned to engage the roller before the crank pin comes to the dead vcenter line. VWith this construction of the roller leading the crank pin, the auxiliary lift may be taken considerably past the dead center line of the crank pin.

With some types of pistons it is advisable to use piston rings engaging the working barrel instead of the piston leathers.

Various changes may be made in the details of the construction Without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. In combination with a double acting pump having a barrel and two independently reciprocable plungers operable therein, means including a pitman for reciprocating each plunger, rotary means for operating the pitmans, and means for elevating each pitman independently of the other pitman at the top of its stroke to a point higher than the rotary means would elevate it.

2. In combination with a double acting pump having a barrel and two independently reciprocable plungers operable therein, means including a pitman for reciprocating each plunger, rotary means for operating the'pitmans, said rotary.

means being rotatable about a stationary axis', and means engageable by the pitmans at the tops of their strokes for elevating each pitman to a point higher than the rotary means would having a barrel andtwo independently reciprocable plungers operable therein, means including a pitman :for reciprocating each plunger, rotary means for operating the ptmans, said rotary means being rotatable aboutra stationary axis, a cam for each pitman` engageable thereby when each pitman approaches the top of its stroke, there being a slip connection between the pitman and the rotary means;

5. In combination with a double acting pump l0 having a. barrel and two `independently recipro- 

